This application claims the priority of German application No. 100 24 256.1, filed May 17, 2000, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a coating solution comprising two or more starting materials for producing a cured coating for preferably metallic surfaces.
In the automotive industry in particular it is common to pretreat metal panels that are intended for later painting. The coats are applied in a multistage process which may include several drying and/or setting phases. The coats include, for example, a corrosion protection coat (e.g., a phosphate coat) and a primer. The application of these coats, or at least some of them, is costly and in some cases may give rise to environmental problems owing to solvents and/or heavy metals.
It is an object of the present invention to prepare a coating solution with which the overall application process is simplified and made less expensive while at the same time the environmental acceptability of the coating solution and of the coating which results from curing the coating solution, is increased as much as possible.
The object is achieved with a coating solution according to the present invention. The aqueous or water-containing coating solution of the present invention comprises a curable, organic-polymeric coating solution which can be employed substantially universally and has a protective and/or anticorrosive and/or adhesion-promoting activity. The coating solution of the present invention is used preferably on bare and/or pretreated and/or precoated metal surfaces and is acceptable in particular to the requirements in car-making. The liquid coating solution may be applied to a large extent universally to any desired substrates, preferably metallic substrates such as, for example, steel, aluminium, magnesium, corresponding alloys, or galvanized steel, directly or else following common pretreatment techniques such as galvanizing, phosphating and chromating, for example.
By the present invention, it is possible to simplify the present very different starting materials and/or coating techniques and/or processes. This simplification is done by omitting process steps, one of the consequences of which is that costs are lowered.
Furthermore, it is possible to use more favorably priced starting materials.
Additionally, the coatings may be applied at lower film thicknesses, as a result of which, for example, the environmental acceptability is improved.
Also of particular advantage with a view to environmental acceptability is that for these coating solutions it is generally possible to forgo additions of heavy metal as a starting material.
In the case of acidic solutions, it is even possible to a large extent to forgo organic solvents. In the case of alkaline solutions, it is even possible to a greater extent to use water as a solvent.